The threads on threaded bolts and similar threaded objects become damaged over time and use. Rather than replace a bolt when it becomes worn, tools have been invented to repair the damaged threads.
The basic design for a thread repair or a die can be seen in Elterich (U.S. Pat. No. 574,721). Elterich shows a die having a threaded cylinder imposed over a cloverleaf design. The cloverleaf allows removal of shavings from the bolt while the bolt is being rethreaded. However, the cloverleaf design compromises the strength of the die. If a bolt is badly damaged, cloverleaf designed dies do not necessarily allow a user to exert heavy torque on the bolt, since the extra pressure may cause the tool to bend, thereby not providing a true rethreading of the bolt. Also, because a large portion of the bolt is generally not in constant contact with the die, the rethreading process is not as smooth as it possibly could be.
To alleviate these problems dies have been designed that may be adapted for use with a wrench, socket driver, or similar device. For example, Kuhn (U.S. Pat. No. 3,715,168) and Baker (U.S. Pat. No. 5,490,746) disclose diestocks that can be used with an ordinary socket wrench. While these devices allow a user to apply more pressure when rethreading a bolt, they are made to conform to a single bolt size. If it is necessary to rethread a bolt of a different size, the diestock must be removed from the ratchet, and the new diestock must be found and connected to the ratchet. This can lead to diestocks being lost or misplaced, and can aggravate the user. The present invention overcomes the disadvantages noted above by providing a sturdy, adaptable rethreading tool.
Not only may bolts need rethreading, but nuts, or internally threaded objects may also need to be rethreaded. As with diestocks, it may not be certain what size tap is needed for a specific nut. The common tap is usually screwed into a chuck or handle, and if a user wishes to change a tap, the tap must be unscrewed and the new tap must be secured to the chuck. This can be a tedious process.
All of the above-noted prior art devices consist of multiple parts that must be assembled prior to use. They are traditionally expensive to manufacture. It is also necessary that all of the component parts must be stored in a container or case. This too adds to the expense of the prior art tools.